Warning: Tfi Control Module Monkey Business

stpete said:

I found some of my old notes cleaning up my office today. I have notes that DY1074 and maybe DY425 are the good old ones and DY1284 and LX218 are the newer generic ones. But, there are several other notes that make me think there are other numbers also. If you go to the dealer or local parts chain and order a DY1074 they will x-ref it to the 1284, sometimes without the counter worker even knowing. Usually the 1074s are the $130-180 ones.
My current one is a 1284. My spare is my old one that sounds similar to yours. I replaced it along with a bunch of other stuff and the car runs much better, but I certainly can't attribute it directly to the tfi as it was one of half a dozen parts replaced.

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Very good info, StP. Thanks for the posting!

89oem said:

Refer to post 15. People who use him all say its the answer.....

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Yuup.. Im definitely gonna go this route. Been lookin at fatfoxx and mcculley kit, but havent seen any postings re folks prefering one over the other. Thoughts?

Just got off the phone with Dave from Wells Vehicle Electronics (maker of Autozone's ignition module testers), and I explained the debacle. He said that once upon a time there were some new Duralast modules that tested bad on their machine, but he didn't know anything about Motorcraft testing bad. He said that if Motorcrafts do uniformly test bad, then it would be surprising that my original unit tested fine when the newer ones test bad. He said he'll look into it further, and he took my number. I'll update when [if] he calls back.

This could have something to do with the different part numbers that stpete mentioned. After a bit more poking around, I found that member, fordjunky, posted a list of module part numbers a few years back (see post 12):
http://www.stangnet.com/mustang-forums/threads/tfi-modules-and-parts-houses.880300/
Looks like the DY-1074s are the new numbers for the old DY-425s.

I'm pretty sure the one currently on the car is factory original, so probably a DY-1074. The branded "real deal" NOS ones I got from ebay were DY-504s (AOD version of 5speed DY-425,) and were advertised as such. The one I got from Ford is a bunk DY-1284 advertised as a DY-425. The ones I got from RockAuto were also DY-1284s, and were advertised as such, but now they are separately listing DY-1074s for $130, which were not listed before. BUT, when you click into the "more info" page for the DY-1074s, they give alternate part numbers, DY1284 and DY425. I wonder if that means that they might just swap-in a $45 DY-1284 for the $130 DY-425 / DY-1074? Or maybe they're just saying they're all the same (if so, why the price difference)?
Man.. this is all too confusing.


Edit: Dave called back! He consulted with someone else and said that the issue might be the particular connector cable the Wells machine uses for our modules; it's coded and labeled as "NB." He said that the NB has had issues in the past, and he asked me to tell the Autozones I've been frequenting to call Wells and order new NB cable. Haha. Good grief..

jrichker said:

Lets hope that when you talk to AutoZone about the Well cable that you don't get "You want to do what with a what?"

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Yeah..typical AZ response. Haha.

I called around to a couple of different AZs and two said that their wells testers are "broken." The one woman said "we havent used that thing since i started working here 2yrs ago." I asked why and she said she was told thay they were giving "faulty readings." Hmm.

Also, back when i talked with dave from Wells i asked him about the resistance testing he said that he didnt have charts on that and that he doesnt think that kind of testing is reliable. I dont know if thats entirely true because, for instance, it seems that the hall effect ground pin should have no resistance to the module base/distributor (which would, in turn, provide ground for hall effect ground pin), no? What do you think, jrichker?

At any rate, its starting to look like there arent reliable tests for our tfi modules.. I suppose all we can do is have faith, install it, and see what happens..

I will call dave again next week to let him know that AZs arent using their wells testers because they are believed to be giving faulty readings. Ill update with his response.

Monkey business aside, I solved my tfi module debacle by doing the relocation kit thing. I used the McCulley Racing kit and a new Wells module, and the car has been running strong for a few weeks now. Thanks for the tip, 89oem!

To summarize what i have learned in the process:

-Wells ignition module testers (the ones Autozone uses) are unreliable. It's not a matter of user error as is often the case with alternator testers (AZ sales assocoates not knowing how to properly use them). The ignition testers are straightforward and dummy proof. The problem is that they are simply not reliable testers.

-The alternative method of checking tfi modules--checking resistance across pins--seems to be equally useless. The Well module I've been running "failed" that check but has been working fine.

-If you have been chasing an intermittent electrical issue, e.g., erratic surging idle, random bucking/stalling while driving, and you have already worked through jrichker's and other tech notes to no avail, the tfi relocation kits are a worthwhile last resort at around $60.

sawdeanz said:

I didn't realize it was so common to have modules DOA. I guess I just got lucky,

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Well, I'm not so sure all (any?) of my modules were DOA after all (can't speak for others). Pretty much came to the conclusion that it was most likely a case of no way to reliably test them, so when my assumption was that there WERE reliable ways to test them, and new modules "failed," it was alarming. I wasn't testing them by installing them in the car, particularly after my experience with LMR when they made it clear that they wouldn't return a part if it had been installed. Now I'm convinced that the only way to really "test" the part is by assuiming it works, installing it, and using it.

sawdeanz said:

only just replaced a TFI module and ignition coil before fixing the problem with a new distributor, but the new Advance Auto Part Store module has survived about 400 miles already.

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Nice. You're probably good to go then--at least for now. I imagine the CHEAP cheap part store modules crap out sooner than the more expensive ones, as others have said.

sawdeanz said:

The old one may be good still after-all so after reading this I will keep for a spare.

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Good plan. Keep a one working one in the car with a TFI tool and thermal grease. Apparently a lot of people do that. I do now, too.

sawdeanz said:

On a semi-related note, where can I borrow a timing light? None of my local stores seem to have a loaner one.

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Yeah.. I never had luck finding loaner tools that handle electricity--seems they only loan mechanical tools in my area. If you live in Northern VA (God help you), then you can use mine. PM me. Otherwise, I'd say hit up Harbor Freight and pick one up. No matter what you do, be sure not to get the CHEAP cheap one. I made that mistake and it did not work straight out of the box. Couldn't even return it because I had it for like a year before I tried using it for the first time. I have had good experience with the "top shelf" timing gun from HF--this one:

http://www.harborfreight.com/timing-light-with-advance-40963.html

Use an ever-available 20% off coupon to get $6 off.